A possible spin Jahn-Teller material: ordered pseudobrookite FeTi2O5
| Autor: | Xu, Hao-Hang, Liu, Jian, Tao, L. L., Wang, Xian-Jie, Streltsov, Sergey V., Sui, Yu |
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| Rok vydání: | 2024 |
| Předmět: | |
| Zdroj: | Physical Review B, 109 (2024) 184430 |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.109.184430 |
| Popis: | We investigated the spin-lattice coupling in orthorhombic pseudobrookite FeTi2O5 single crystal with highly ordered $ Fe^{2+} / Ti^{4+}$ occupation, which consists of quasi-1D S=2 chains running along a-axis. Both the magnetization and specific heat measurements confirm that the antiferromagnetic phase transition of FeTi2O5 occurs at TN = 42 K. The structural distortions were also observed around TN in the thermal expansion $ \Delta L / L (T)$ data. Moreover, the magnetic field was found to strongly affect the thermal expansion both along chains and in the perpendicular direction clearly signaling a substantial magnetoelastic coupling, which was recently proposed to be the origin of a rare spin Jahn-Teller effect, when frustration is lifted via additional lattice distortions. Experimentally observed change in the thermal conductivity slope around TN is usually associated with the orbital ordering, but DFT+U calculations do not detect modification of the orbital structure across the transition. However, the first-principles calculation results confirm that FeTi2O5 is a quasi-1D magnet with a ratio of frustrating inter-chain to intra-chain exchanges $ J' / J = 0 . 0 3$ and a substantial single-ion anisotropy (A = 4K) of easy-axis type making this material interesting for studying quantum criticality in transverse magnetic fields. Comment: 20 pages, 7 figures |
| Databáze: | arXiv |
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